The present invention relates to an infrared sensor comprising an array of resistance bolometer infrared (IR) detectors.
A resistance bolometer infrared detector is typically operated in a resistive potential divider configuration in which one resistor (the sensing bolometer) has a variable resistance due to incident infrared radiation and a second resistor has a substantially constant reference resistance. Typically the reference resistor is constructed in a similar fashion to the sensing bolometer to provide matching over manufacturing tolerances, but constructed in such a way that the thermal conductivity between the bolometer and the substrate is much higher than for the sensing bolometers. In this circuit configuration, the resistive potential divider would be driven with fixed voltage sources. The infrared radiation would then be detected by sensing and measuring a voltage change at the centre connection node of the potential divider caused by the change in resistance in the detector bolometer. In a bolometer array, the driving voltages would be connected to all bolometer elements (potential dividers) in the array. Typically, such bolometers would be connected to an amplifier through a multiplexing switch arrangement. Because all bolometers are connected in this common fashion, there is no means of providing a test stimulus to the individual bolometers that can clearly isolate bolometers from their near neighbours to determine the existence of manufacturing and circuit faults.